Porcelain enameled tank



Filed June 20, 1945 INVENTOR.

WILLIAM H. MART/N ATTORNEYS fiatentecl Jan. 30,

PORCELAIN 'ENAMELED TANK William H. Martin, Lakewood, Ohio, assignor toR elilffil ib Ilfdfilil ie s, 1110., .New York, N. Y., a

corporation of Delaware Applicationtl'une 20, 1945, Serial No. 600,446

'5 Claims. 01. 29-1482) This invention relates as indicated to tanks andmore especially to hot water tanks such as are used in homes and similarplaces for the storage of domestic hot water. More particularly thisinvention relates to tanks of the character described which are providedwith a coating over their entire inside surface of porcelain -enamel}whereby rusting or similar deterioration of the tank is reduced to aminimum.

In the manufacture of tanks of this kind, it is necessary to separatelyenamel the interior surfaces of the shell and the heads which whenultimately assembled in the ends of the shell form the closed tank. Thisprocedure of separately enamelling the three principal parts of the tankis necessary in order that such wparts may be inspected to determine thepossible existence of pin holes or other minute imperfections which ifpresent would nullify to a great extent the protection afforded by theremainder of the coat.

When the three component parts of the tank are thus enamelled prior totheir assembly, they are, of course, heated to a relatively hightemperature in order to fuse the enamel and fix thesame to the metalbody. This heating to which the tank parts are subjected has a tendencyto warp or otherwise distort the parts so that close fitting-'engagernent between :the heads and tank body is interfered with whenthe em amelled parts are subsequently sought to be as-' sembled. In anattempt to obviate this dithculty, it has-been proposed to make the endsof the tank and the heads coniform so that they may be assembled by awedging action brought about by the exertion of a very considerablepressure in forcing or wedging the-coniform head into the flared orconiformed end of the tank. Thi Wedging expedient performed under highpressures will deform the warped or otherwise 2 cracking or otherwisebreaking the enamel coating, but which also insures that the partsduring the enamellin-g operation will be warped :to a minimum extent :sothat assemblage of the component parts in close fitting relation ispossible.

Other objects of the invention will appear: as the description proceeds.

To the accomplishment of. the foregoing and related ends, said inventionthen comprises the features hereinafter fully described and particularlypointed out in claims, the following description .and the annexeddrawing setting forth in detail certain illustrative embodiments of theinvention, these being indicative, however, of but a few of the variousways in the principle of the invention may be employed.

In said annexed drawing, the single figure is a transverse sectionalview of-a -tank=constructed in accordance with the principles of myinvention.

first provide a cylindrical shell generally indi- 3 cated at I which hasa uniform inside diameter out-of-round parts sufficiently to bring theminto proper alignment. However, in doing so, cracks are frequentlydeveloped in the enamel coating and where .a crack occurs, the contentsof the tank can come .into contact'with the metal body of the tank anddeterioration in such "a local area soon spreads to the point where theentire tank body has a life not substantially greater than a tank whichis not provided with an enamel coating.

It is a principal object of my invention to provide a method offabricating tanks of the character described which will not only producecomponent parts which can be readily assembled without pressures such ashave the efiect of ameter of the body the shell is increased in from endto end. These cylindrical shells can be provided from either piercedseamless t-ubing or from 'flat sheets which are circularize'd and thenwelded along a longitudinally extending sea-m. Irrespective of theprecise manner "inwhich these shells are provided, they will "be foundto have present therein certain-stresses incidental to theirfabrication, which, during the temperatures encountered in theenamelling operation, cause "the "shell to warp 'or similarly distort.

'Kfter'th'e shell of appropriate "length and inside "diameter has beenthus provided, I expand each end of the shell into a cylindricalextension genera-Hy indicated at 2 which has an iriside diameter Asubstantially greater than the inside diameter or the main body l of the'shell. The extension 2 iscylindricail' form. It is pro vided preferablyby cold working and the diprcviding the extension 2 by an amount sufiicient to impart in set.

After the shell has been thus expanded at each end and given a permanentset in the cylindrical area 2 to a diameter slightly greater than theinside diameter of the body of the shell, the latter is then enamelledthroughout the entire axial extent of its inside surface by aconventional enamelling procedure which forms no part of the presentinvention. It will be found that when In carrying out the process of myinvention 1 such extension a permanent 3 the shell thus preliminarilyformed is enamelled, it will not be warped or otherwise changed in sizeor shape to any material extent.

I next provide a dished sheet generally indicated at 3 which has acylindrical marginal flange or skirt 4 with an outside diameter at leastslightly smaller than the inside diameter of the cylindrical extension2. The head 4 after being thus provided is then enamelled on its upperor inside surface, after which it is telescopically assembled in the endof the shell and maintained in assembled relation by means of a filletweld 5 which extends around the entire periphery of the assembly. When aprocess such as that described above is employed, the parts may bemaintained in sufiiciently closely fitting relation so that theutilization of gaskets between the head and body of the tank is notnecessary.

While the shape of the dished head 3 is such that the cylindrical formof the flange or skirt is generally maintained without difficulty andwithout substantial variation during the subsequent enamellingoperation, it is, nevertheless, also within the contemplation of myinvention to include as the last forming step in the manufacture of thehead 3 a radial stretching of the cylindrical flange 4 sufliciently toimpart thereto a permanent set in the cold worked condition similarly tothe manner in which the cylindrical extension 2 has been formed.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims or the equivalent of suchbe employed.

I, therefore, particularly point out and distinctly claim as myinvention:

1. The method of making a porcelain enamel lined hot water tank whichcomprises providing a cylindrical steel shell, expanding one end of saidshell sufficiently to provide a cylindrical terminus thereon having apermanent set with an inside diameter greater than the inside diameterof said shell and joined to said shell by an abrupt shoulder, providinga head having a cylindrical marginal flange Whose outside diameter issubstantially that of said shell and only slightly less than the insidediameter of said cylindrical enlargement, porcelain enamelling theinside surface of said shell and the outer surface of said flange onsaid head, telescopically assembling said shell and head with the latterabutting said shoulder and the cylindrical flange wall of the head inprojection alignment with the cylindrical wall of the shell, and fusionwelding the end of said extension to said head.

2. The method of making a porcelain enamel lined hot water tank whichcomprises providing a cylindrical steel shell, by means of cold workingexpanding one end of said shell sufliciently to provide a cylindricalterminus thereon having a permanent set with an inside diameter greaterthan the inside diameter of said shell and joined to said shell by anabrupt shoulder, providing a head having a cylindrical marginal flangewhose outside diameter is substantially that of said shell and onlyslightly less than the inside diameter of said cylindrical enlargement,porcelain enamelling said shell and head, telescopically assembling saidshell and head with the latter abutting said shoulder and thecylindrical flange wall of the head in projection alignment with thecylindrical wall of the shell, and fusion welding the end of saidextension to said head.

3. The method of making a porcelain enamel lined hot water tank whichcomprises providing a cylindrical steel shell, by means of cold workingexpanding one end of said shell sufficiently to provide a cylindricalterminus thereon having a permanent set with an inside diameter greaterthan the inside diameter of said shell and joined to said shell by anabrupt shoulder, providing a head having a cylindrical marginal flange,by means of cold working radially expanding such flange to an outsidediameter substantially that of said shell and only slightly less thanthe inside diameter of said cylindrical enlargement, porcelainenamelling said shell and head, telescopically assemblingsaid shell andhead with the latter abutting said shoulder and the cylindrical flangeWall of the head in projection alignment with the cylindrical wall ofthe shell, and fusion welding the end of said extension to said head.

4. In the manufacture of porcelain enamel lined tanks having acylindrical steel shell and a dished head, the steps of expanding an endof the shell out to an abrupt shoulder and a terminus of cylindricalform with inside diameter greater than that of said shell, providing ahead with a marginal flange in cylinder form and outside diametersubstantially that of said shell and slightly less than the insidediameter of said cylindrical terminus, porcelain enameling said shelland head, seating said head in said cylindrical terminus against saidshoulder and the cylindrical flange wall of the head in projectionalignment with the cylindrical wall of the shell, and welding the edgesof theshell and head together.

5. In the manufacture of porcelain enamelwall of the shell, and weldingthe edges of the shell and head together.

WILLIAM H. MARTIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 774,041 Cofiin Nov. 1, 19041,748,577 Merriam Feb, 25, 1930 2,015,193 Reed Sept. 24, 1935 2,197,609Cornell Apr. 16, 1940 2,263,021 Uecker Nov. 18, 1941 2,335,153 LauckNov. 23, 1943 2,363,990 Priebe Nov. 28, 1944

